Rail bond



April J. R. WILSON 2,240,199

RAIL BOND Filed April 2'7, 1940 IN TOR John i/son Patented Apr. 29, 1941 RAIL BOND John R. Wilson, Wilkinsbnrg, Pa., assignor to Hanlon and Wilson Company, a corporation of Pennsylvania Application April 27, 1940, Serial No. 331,986

5 Claims.

The present invention relates broadly to conductors, and, more particularly, to conductors for connecting the adjacent ends of railway rails, particularly those for use in connection with railway track circuits.

In the raflway signaling art the ordinary rail connecting or fish plates connecting the adjacent ends of the rails cannot be relied upon to furnish sufficient conductivity for the electrical energy which flows in the rails from the battery at one end of the section to the relay at the other end thereof. This fact has made it necessary to provide special bonding of each of the adjacent abutting rail ends within any given section.

Considerable diiliculty has been encountered in successfully bonding the adjacent abutting rail ends in track circuit sections because a number of adverse conditions have to be taken into consideration. In one of the common methods in use at the present time, the electrical connection between the rails is effected by placing the ter minals in holes in the webs of the adjacent rails and by providing a conductor extending between the terminals having a length somewhat greater than the length ofthe fish plates joining the rails. This method of bonding is objectionable as it exposes the bonding wires to mechanical injury. They become entangled with dragging parts from the rolling stock and at times they work up to the tops of the rails and the rolling stock runs over them and severs them. In addition, trackmen working on the roadbed in and around the rail. joint are likely to damage such bonds. Another pronounced difliculty with this type of bond is that due to its length and in spite of its size, it does not offer a conductivity as great as is desired, and this desired conductivity cannot be obtained without increasing the .size of the bond to a prohibitive extent.

Heretofore it has been proposed to overcome the difliculties encountered with the type of rail bond mentioned above by providing a relatively short bond having terminal portions positioned in cavities in the heads of adjacent rail ends. While this type of bond overcomes the various difficulties mentioned above with regard to the old type of bond, those rail head bonds which have been utilized heretofore have been objectionable from several standpoints.

One form of rail head bond which has been.

used heretofore embodies a soft metal piece extending into that portion of the terminal which is positioned in the rail cavity, this piece extending through the bottom end thereof, so that upon driving the bond into the hole by means of a sledge hammer the relatively soft metal will be forced into the end section of the terminal and will cause it to expand into tight engagement with the walls of the rail cavity. In another type of rail head bond which has been used heretofore, a relatively thin metallic sleeve extends into the rail cavity and a small pellet of soft metal is placed in the hollow sleeve portion and a driving and expanding tool then used in conjunction with a hammer to expand the soft metal pellet radially of the sleeve so as to expand the sleeve into intimate contact with the side walls of the rail cavity. In addition, it has also heretofore been proposed to utilize tapered pins for expanding the terminal positioned in the rail cavity into tight engagement with the side walls.

All of these types of bonds have been found objectionable for one reason or another. The first type mentioned above is objectionable as is cannot be reused. It is also objectionable as the engagement between the terminal and the cavity walls is not suificiently tight to avoid loosening by excessive vibration. The second type mentioned above is objectionable as it requires the use of a special expanding tool, and in view of the fact that a sufliciently tight engagement cannot be obtained in case the rail cavity is not of the proper size. Under such circumstances the extreme vibrations to which the bonds are subjected will cause a loosening of the bond over a period of time. This type is objectionable also as there is a possibility that the man installing the bond will not properly concentrate the expanding forces so that they will be most eflective throughout the full area of the rail cavity. The third type mentioned above is objectionable as it requires the use of a loose pin. This type is also objectionable as the expansion pin becomes loosened due to the excessive vibrations and the bond will frequently fall out of the rail cavity.-

The bond which I provide by the present invention overcomes all of the objectionable features mentioned above. By the present invention I provide a bond the terminals of which can be positioned in the rail cavity and the sleeve or end section of the bond readily expanded into exceptionally tight engagement with the walls of the cavity by merely striking the driving and expanding pin with ahammer. In accordance with my invention the drive pin may be made separately and positioned and locked in the bore of theterminal after it is mounted in the rail cavity, or it can be appropriately positioned in the bore of the terminal and locked in position at the time of manufacture. It will readily be appreciated that this is a definite advantage over those types involving the use of a separate pellet and a separate driving tool, as the drive pin, where it is placed in the bore of the terminal when manufactured, is always in place both for the first drive and for any subsequent removal and reapplication of the bond. In the bond which I provide the pin is properly locked in position and it cannot fall out due to the vibrations to which it is subjected in use or due to the differences in the expansion rates of the different metals or other materials embodied in the terminal. Another advantage of the bond which I provide is that, even though the drive pin is tapered to some extent during the driving operation due to variations from the proper dimensions of the terminal andcthe pin, the action of this taper coupled with the vibrations cannot cause the pin to fall out of place as the pin is definitely locked in position during or before the final driving operation takes place. Another definite advantage of the bond which I provide is that by locking the pin in appropriate position prior to the final driving operation the expanding forces are concentrated in such a way that they will be exerted relatively uniformly throughout the full area of the hole or cavity in the rail, with the result that a very tight and substantially permanent engagement is effected between the terminal and the rail. Another advantage in the type of bond which I provide is that the flow of the fluid (which may be a soft metal or some other material capable of flowing under pressure) in the sleeve of the terminal is concentrated within the sleeve so as to provide a greater range of expansion in the sleeve portion. a.

In the accompanying drawing I haveshown my invention as applied to a bond of the railhead type. The present invention is particularly useful in bonds of this type but it will be evident from what is stated herein that it may be embodied in bonds of various types other than the rail head type. In the accompanying drawing I have shown for purposes of illustration only a preferred embodiment and several modified forms of bonds embodying my invention. In the drawing:

Figure 1 is a side elevational view of two adjacent rail ends with the improved bond which I provide in place;

Figure 2 is a section taken along the line 11-11 of Figure 1;

Figure 3 is a sectional view similar to Figure 2 showing a modified form of my invention;

Figure 4 is a view similar to Figure 2 showing another embodiment of my invention;

Figure 5 is a view similar to Figure 2 showing another embodiment of my invention;

Figure 6 is a view similar to Figure 2 showing another embodiment of my invention;

Figure 'l is a view similar to Figure 2 showing a still further embodiment of my invention; and

Figure 8 is a partial plan, partial section of a pin which may be utilized in carrying out my invention, and in which the material used for effecting the expansion of the sleeve has been molded or otherwise formed on the end of the pin prior to the time that it is placed in the bore of the terminal.

Referring first to Figures 1 and 2, the terminals 2 are adapted to extend into holes or cavities 3 in the rail heads 4. These terminals are joined together by a conductor 5 which is secured by welding or in some other suitable manner to the terminals. Each terminal 2 embodies a head section 6 and an end section or sleeve I, the latter of which extends into the cavity 3 in the rail. The head 6 is preferably of a larger cross-sectional area than the sleeve portion I in order to give rigidity to the outer end of the terminal and in order to provide a sufilcient cross-sectional area to enable a proper connection with the conductor 5. The terminal is provided with a centrally disposed bore 8 which extends completely through the head 6 and throughout a substantial portion of the length of the sleeve 1. This bore preferably extends into the sleeve a sufilcient distance so that the bottom wall 9 of the terminal which rests against the inner end of the rail cavity 3 is of approximately the same thickness as the side walls of the sleeve.

The expansion of the end section or sleeve portion of the terminal into tight engagement with the walls of the cavity is effected by means of a pin l0 and a material ii which is capable of flowing under pressure and which is positioned in the bore in the sleeve portion of the terminal. The pin iii is provided with a reduced end section l2 adapted to be embedded and locked in the material ii. The diameter of the main bodyportion ii of thepin is substantiallythe same as the diameter of the bore of the terminal, so that it will fit snugly against the walls of the bore throughout the head and throughout a portion of the length of the sleeve. The pin III is of such length that one end thereof will project beyond the face of the head 6 so that when the terminal is positioned in the cavity the pin can be driven by means of a hammer axially of the terminal in order to effect the expansion of the sleeve. The body portion I: of the pin III is preferably of uniform diameter throughout its length, and it is preferably of such length that when the sleeve is placed in the rail cavity the shoulder between the reduced end section II and the body portion i 3 will be approximately in line with the rail head or will extend just a slight distance into the rail cavity, so that when the pin is driven the expansion forces will be confined to the cavity in the rail. The reduced end section I 2 of the pin is preferably of suchconfiguration that the crosssectional area thereof adjacent the shoulder of the body portion is smaller than an adjacent section toward the end of the pin, in order to facilitate the locking of the pin in the terminal. The end of this reduced portion is also preferably beveled so as to facilitate the axial movement of the pin when it is driven.

The sleeve of the terminal which extends into the rail cavity is preferably of such a length that when it is bottomed in the cavity, and when the pin is driven into position and the sleeve expanded. a slight space will exist between the rail head and the body of the terminal in order to facilitate the removal of the termina1 from the rail if, for any reason, it is desired to remove it and use the bond elsewhere.

' The fluid Ii may be any suitable material which is substantially noncompressible and which will flow under pressure. I preferably employ a soft metal such as copper, although it will be evident to those skilled in this art that various other materials and various other metals may be employed. As a snug fit may not be obtained in all cases it is preferable to employ a soft metal or some other similar material which will flow under pressure, and which will not have an undue tendency to work its way through any small clearance that there may be between the pin and the bore.

In Figure 2 the terminal is shown as placed in the rail cavity prior to the driving operation. When so located it is merely necessary to drive the pin axially to the left, as shown in Figure 2, in order to cause the copper II to expand the sleeve radially into tight engagement with the walls of the cavity, and axially into tight engagement with the bottom of the rail cavity.

While I preferably embed the reduced end of the pin in the soft metal ll during the manufacturing operation and prior to the time that the terminal is placed in the rail cavity, it will be evident that the terminal, the soft metal pellet I l and the pin may be delivered for use separately, and the terminal then placed in the cavity, the pellet of soft metal placed in the bore of the terminal and the pin then placed and driven into position. It will also be evident that if desired the pin and the soft metal may be supplied as a separate piece. As indicated in Figure 8, the soft metal l5 may be molded around the reduced end I6 of the pin II. The terminal and this pin may then be supplied to the purchaser separately and it will only be necessary for the user to place the terminal in the rail cavity and to then place the pin in the bore of the terminal and drive it to position.

In the embodiment shown in Figure 3 the terminal I8 is the same as the terminal of the embodiment shown in Figure 2 but the pin I9 is provided with a modified reduced end portion 20. In this embodiment the inner end of the pin has a cross-sectional area less than that of the main body portion but greater than the part of the end section adjacent the shoulder 2| of the body portion. As in the case of the pin shown in Figure this arrangement permits the soft metal to flow around the reduced end and to positively lock the pin in position.

In the embodiment shown in Figure 4 the pin 22 is provided with a different form of reduced end. In this embodiment the reduced end section 23 is of uniform diameter throughout its length but it is provided with a centrally disposed hole 24 into which the soft metal will flow. The soft metal will flow into this hole and around the outer portion of the reduced end section 23 and will lock the pin in position.

In the embodiment shown in Figure 5 the pin 25 is provided with a somewhat different form of reduced end section 26. In this embodiment the portion of the reduced end adjacent the shoulder 21 of the body portion of the pin is smaller in cross section than a portion thereof further from the shoulder, so that the soft metal will flow around the reduced end and lock the pin in position.

In Figure 6 the pin 28 has a still different form of reduced end section 29 which is provided with grooves 30 and 34 which facilitate the locking of the pin into position by the soft metal.

In the embodiment shown in Figure 7 the pin 32 has a still different form of reduced end section 33. In this form the metal fiows around the reduced end section and locks the pin in position.

It will be evident from what has been stated above that the rail bond which I provide overcomes the various difficulties mentioned above. This bond is of such character that the pin will be locked in position and will remain there indefinitely without any substantial reduction of the expansive forces holding the terminal in position in the rail cavity.

While I have shown and described a preferred embodiment and several modifications of my invention, it will be understood that I do not intend to be limited thereby and that my invention may be otherwise embodied within the scope of the appended claims.

I claim:

1. A rail bond terminal comprising a head. an expansible sleeve portion integral with the head adapted to be inserted in a. rail cavity, a bore extending through the head and through a substantial portion of the length of said sleeve, one end of the bore being closed by the end wall of the sleeve, a relatively soft metal in the inner end of the bore of said sleeve, and a pin having a body portion and a reduced inner end portion, the body portion of the pin having a cross section substantially the same as that of the bore so as to substantially completely fill the bore and the reduced end portion being shaped for interlocking engagement with said soft metal, whereby upon driving the pin axially in said bore the reduced end section of the pin is driven into said material and the pin locked in the terminal.

2. A rail bond terminal comprising a head, an expansible sleeve adapted to be inserted in a rail cavity, a bore extending through the head and throughout a substantial portion of the length of said sleeve, one end of the bore being closed by the end wall of the sleeve, a soft metal in the base of the bore in the sleeve, and a pin having a body portion and a reduced end portion extending into the sleeve, the body portion of the pin having a diameter substantially that of the bore in order to provide a tight fit therewith, the reduced end section of the pin having a portion adjacent the body portion of the pin of lesser cross sectional area. than the portion of the reduced section further away from the body portion of the pin, whereby upon driving the pin into the soft metal in the base of the bore the metal will flow around the reduced end section of the pinand lock it in position in the terminal.

3. A rail bond terminal comprising a head, an expansible sleeve adapted to be inserted in a rail cavity, a bore extending through the head and throughout a substantial portion of the length of the sleeve, one end of the bore being closed by the end wall of the sleeve, 2. material capable of flowing under pressure filling the inner end of the bore in said sleeve, and a pin having a diameter substantially that of the bore throughout a substantial portion of its length positioned in the bore, said pin having a reduced end section adapted to be driven into said material to cause it to expand the sleeve of the terminal into tight engagement with the rail cavity, said reduced end section being formed for interlocking engagement with said material. when driven therein, the shoulder between the body portion of the pin and the reduced end section extending into said sleeve to approximately the face of the rail prior to the driving of the pin for expanding the sleeve into engagement with the rail cavity.

4. A rail bond terminal comprising a head, an expansible sleeve adapted to be inserted in a rail cavity, a bore extending through the head and throughout a substantial portion of the length of said sleeve, one end of the bore being closed by the end wall of the sleeve, a soft metal in the base of the bore in the sleeve, and a pin having a body portion and an inner end portion extending into the sleeve, the body portion of the pin having a diameter substantially that of the bore in order to provide a tight fit therewith, the inner end section of the pin being shaped for interlocking engagement with said soft metal, whereby upon driving the pin into the soft metal inthe bore the metal will interlock with the inner end section of the pin and lock it in position in the terminal.

5. In a rail bond, the combination of a terminal having a sleeve portion adapted to be positioned in a rail cavity and having a bore extending into said sleeve and opening through the other end of said terminal, a pin adapted to be positioned in said bore, said pin having a body portion of a diameter substantially the same as that of the bore and a reduced end portion adapted to be positioned within the bore in the sleeve, said reduced end portion having at least one circumferential groove therein and a substantially non-compressible material capable of flowing under pressure adapted to be placed in the bottom oi the bore in the sleeve, whereby upon driving the pin into the bore the sleeve is expanded and interlocking engagement provided between the pin and said material.

JOHN R. WILSON. 

